Optical and electrochemical properties of novel fused tricyclic thiophene–15-crown-5 systems and their complexes with Mg and Ba ions

Congestion effect of an annulated tetracyclic thiophene-containing fragment on 18-crown-6 ether: manifestation in complex formation in solution and membrane transfer properties

“…1) were synthesized by the Mallory–Katz photocyclization route from stilbene 3 obtained accordingly from (3-benzothienyl)methylphosphonate 4 and formylbenzo-18-crown-6 5 by the Horner–Wadsworth–Emmons reaction. Phosphonate 4 was synthesized from 3-methylbenzothiophene 6 by the bromination-Arbuzov reaction sequence (Scheme 1) As expected, a mixture of two products is formed, 31,32 which were isolated by column chromatography.…”